stk-code_catmod/src/items/cake.cpp
2018-07-25 15:33:49 +08:00

165 lines
6.2 KiB
C++

//
// SuperTuxKart - a fun racing game with go-kart
// Copyright (C) 2007-2015 Joerg Henrichs
//
// Physics improvements and linear intersection algorithm by
// Copyright (C) 2009-2015 David Mikos.
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 3
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#include "items/cake.hpp"
#include "io/xml_node.hpp"
#include "karts/abstract_kart.hpp"
#include "utils/constants.hpp"
#include "utils/random_generator.hpp"
#include "utils/log.hpp" //TODO: remove after debugging is done
float Cake::m_st_max_distance_squared;
float Cake::m_gravity;
Cake::Cake (AbstractKart *kart) : Flyable(kart, PowerupManager::POWERUP_CAKE)
{
m_target = NULL;
setDoTerrainInfo(false);
btVector3 gravity_vector;
btQuaternion q = kart->getTrans().getRotation();
gravity_vector = Vec3(0, -1, 0).rotate(q.getAxis(), q.getAngle());
gravity_vector = gravity_vector.normalize() * m_gravity;
// A bit of a hack: the mass of this kinematic object is still 1.0
// (see flyable), which enables collisions. I tried setting
// collisionFilterGroup/mask, but still couldn't get this object to
// collide with the track. By setting the mass to 1, collisions happen.
// (if bullet is compiled with _DEBUG, a warning will be printed the first
// time a homing-track collision happens).
float forward_offset=kart->getKartLength()/2.0f + m_extend.getZ()/2.0f;
float up_velocity = m_speed/7.0f;
// give a speed proportional to kart speed. m_speed is defined in flyable
m_speed *= kart->getSpeed() / 23.0f;
//when going backwards, decrease speed of cake by less
if (kart->getSpeed() < 0) m_speed /= 3.6f;
m_speed += 16.0f;
if (m_speed < 1.0f) m_speed = 1.0f;
btTransform trans = kart->getTrans();
float heading=kart->getHeading();
float pitch = kart->getTerrainPitch(heading);
// Find closest kart in front of the current one
const bool backwards = kart->getControls().getLookBack();
const AbstractKart *closest_kart=NULL;
Vec3 direction;
float kart_dist_squared;
getClosestKart(&closest_kart, &kart_dist_squared, &direction,
kart /* search in front of this kart */, backwards);
// aim at this kart if 1) it's not too far, 2) if the aimed kart's speed
// allows the projectile to catch up with it
//
// this code finds the correct angle and upwards velocity to hit an opponents'
// vehicle if they were to continue travelling in the same direction and same speed
// (barring any obstacles in the way of course)
if(closest_kart != NULL && kart_dist_squared < m_st_max_distance_squared &&
m_speed>closest_kart->getSpeed())
{
m_target = (AbstractKart*)closest_kart;
float fire_angle = 0.0f;
getLinearKartItemIntersection (kart->getXYZ(), closest_kart,
m_speed, m_gravity, forward_offset,
&fire_angle, &up_velocity);
// apply transformation to the bullet object (without pitch)
btQuaternion q;
q = trans.getRotation() * btQuaternion(btVector3(0, 1, 0), fire_angle);
trans.setRotation(q);
m_initial_velocity = Vec3(0.0f, up_velocity, m_speed);
createPhysics(forward_offset, m_initial_velocity,
new btCylinderShape(0.5f*m_extend),
0.5f /* restitution */, gravity_vector,
true /* rotation */, false /* backwards */, &trans);
}
else
{
m_target = NULL;
// kart is too far to be hit. so throw the projectile in a generic way,
// straight ahead, without trying to hit anything in particular
trans = kart->getAlignedTransform(pitch);
m_initial_velocity = Vec3(0.0f, up_velocity, m_speed);
createPhysics(forward_offset, m_initial_velocity,
new btCylinderShape(0.5f*m_extend),
0.5f /* restitution */, gravity_vector,
true /* rotation */, backwards, &trans);
}
//do not adjust height according to terrain
setAdjustUpVelocity(false);
additionalPhysicsProperties();
} // Cake
// -----------------------------------------------------------------------------
/** Initialises the object from an entry in the powerup.xml file.
* \param node The xml node for this object.
* \param cakde_model The mesh model of the cake.
*/
void Cake::init(const XMLNode &node, scene::IMesh *cake_model)
{
Flyable::init(node, cake_model, PowerupManager::POWERUP_CAKE);
float max_distance = 80.0f;
m_gravity = 9.8f;
if (m_gravity < 0) m_gravity *= -1.0f;
node.get("max-distance", &max_distance );
m_st_max_distance_squared = max_distance*max_distance;
} // init
// ----------------------------------------------------------------------------
/** Callback from the physics in case that a kart or physical object is hit.
* The cake triggers an explosion when hit.
* \param kart The kart hit (NULL if no kart was hit).
* \param object The object that was hit (NULL if none).
* \returns True if there was actually a hit (i.e. not owner, and target is
* not immune), false otherwise.
*/
bool Cake::hit(AbstractKart* kart, PhysicalObject* obj)
{
bool was_real_hit = Flyable::hit(kart, obj);
if(was_real_hit)
{
if(kart && kart->isShielded())
{
kart->decreaseShieldTime();
return false; //Not sure if a shield hit is a real hit.
}
explode(kart, obj);
}
return was_real_hit;
} // hit